Examples of conventional welding materials for use at temperatures as low as -90.degree. C. are 3.5% nickel alloy steel and austenite stainless steel.
Welds with these materials, however, offer low yield strengths of 30-55 Kgf/cm.sup.2, although they are durable at low temperatures, which precludes their use for rotary high-speed machinery which requires materials that can be used as welding materials in strong and durable states at low temperatures. Additional heat treatment-- quenching and tempering do not raise yield strength and impact value, VE-- 90 to permit such welds being used in parts subject to high r.p.m.